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Which three orbital cycles are included in the astronomical theory of ice ages?
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Quaternary
Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the Quaternary Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.
The astronomical theory of ice ages, often referred to as Milankovitch cycles, identifies three primary orbital parameters that influence the distribution of solar radiation on Earth and drive long-term climatic changes:123
- Eccentricity: This refers to the shape of Earth’s orbit around the Sun, which varies from nearly circular to more elliptical over a cycle of approximately 100,000 years.123
- Obliquity (Tilt): This is the angle of Earth’s axial tilt relative to its orbital plane. It varies between 22.1° and 24.5° over a cycle of about 41,000 years, significantly impacting seasonal climate intensity.123
- Precession: This is the "wobble" of Earth’s axis of rotation combined with the rotation of the orbital ellipse. It changes the orientation of the axis relative to the Sun and operates on cycles of approximately 19,000 to 23,000 years.123
These cycles interact to alter the amount of insolation received at different latitudes, acting as the "pacemaker" for the advance and retreat of glacial periods throughout the Quaternary period.123